Johnson was Tottenham’s leading Premier League goalscorer last season with 11, and etched his name in Spurs folklore by scoring the winner in their Europa League final triumph over Manchester United in Bilbao, ending the club’s 17-year wait for a trophy.
But the departure of Ange Postecoglou and arrival of Thomas Frank as new head coach has meant Johnson has played more of a peripheral role this season.
Johnson, 24, has made only six top-flight starts under Frank this season.
As a result, a number of clubs have been alerted to his potential availability before the January transfer window.
Given his lack of action and the prospect of a World Cup on the horizon with Wales, a move away from Tottenham may suit Johnson next month.
Johnson joined Tottenham from Nottingham Forest in a deal worth £47.5m in the summer of 2023 and has scored 27 goals for the club.